Method of obtaining water-soluble azo dyes



Patented Apr. 21, 1931 IWAN osrnotnsLEnsKY, or new Yon N. assreiron Toma nered abatem- TION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORKMETHGD or OBTAINING wi sasosegrsa omss No Drawing. Ori inal applicationfiled March 28, 1926;81ria1 17 0397371";

, filed September 23, 1927. Serial ITO; 221-3630.

lhis invention is an improvement in a method of makingaryl-azo-diamino-pyridine dyes easily soluble in water, and the presentapplication is a division of Patent NO. 1,680,109, granted August 7th,1928.

In the investigation of the reactions be tween diazotized aromaticamines and alphaalpha-diaminopyridines, as pointed out in my PatentsNos. 1,680,108 and 1,680,109, granted 7 V of other azo-dyes, such aspara-amino-phenylazo-benzol-hydrochloride, or diamino-pyridinehydrochloride.

1 have found that this substance composed of the compounds, namely; theisomers of phenyl-azo-diaminopyridine hydrochloride, melting point 137(1., and 203 (3., respectively, and diphenyl-diazo-diaminopyridinehydrochloride, melting point 215 (1, is while but slightly toxic,strongly bactericidal, for which reason it is of value as a medicinalpreparation in a variety of infectious diseases.

. To make this substance easily soluble in 7 water, salts or" othersoluble azo-dyes, such as para-amino-phenyl-azo-benzol-hydrochloride orsalts of naphthylamines, and the like,

should be added to its hydrochloride. The

above-mentioned compounds in pulverulent form, when mixed togethermechanically in boiling water, absorbs one another easily and rapidly,and upon cooling the resultant solution forms a stable and altogetherhomogeneous preparation with a relatively strong bactericidal action. I

In particular, a very valuable absorbent substance composed of theisomers of phenylazo-diaminopyridine-hydrochloride, with aphenyl-azocertain amountof diphenylediazoi-diaminopyridmehydrochlorideis obtained directly in-the coupling reaction, by adding tothe acid solutionjmade up of one molecule of alpham-lpha-diaminopyridinean acid solu-s tion; of diazotized' aniline -to the amount-{of not lessthan one-haltand'not' morethan two: molecules; i The absorbent;co1"npou-n'dIvv of pyridine azo-dyes formed by this reaction" hasthe-following formula I so a I, 2 c t 8 3 In this connection it may beisolated from themono-phenyl isomers, since the hydrochlorides of themono-phenyl' isomers are much more soluble in water than the diphenyl.Following are examples of the procedure Examples (a). 100 gms.hydrochloride of phenylazo- (gamma) -alpha alpha diaminopyridine and 150set para-amino-phenyl-azobenzol-hydrochloride, are dissolved in boilingwater, and are allowed to recrystallize therefrom. V (b). 100 gms.phenyl-azo- (gamma) -alphaalpha-diaminopyridine hydrochloride and 100gms. of mono-phenyl-azo-diaminopyridine hydrochlorides in powder aredissolved in boiling water and allowed to recrystallize therefrom.

The product from both processes (a and b) is homogeneous'and stable,forming easily .3

to-1% aqueous solutions. To insure complete disappearance of the redcoloring, 50 c. c. of a 0.5% solution of the product of process (6)requires 10 to 12 c. c. of a N/lO solution of sodium hydroxide.

What is claimed as new is 1. In the method of making aryl-azor. 170stated that the diphenyl-diazo-diamino-pyridine may bealpha-alpha-diaminopyridine easily soluble in water, the step whichconsists in mixing agueous solutions of the salts with azo-dyes o thebenzol, naphthaline or pyridine series.

2. In the method of making aryl-azoalpha-alpha-diaminopyridine easilysoluble in water, the step which consists in mixing apueous solutions ofthe salts with azo-dyes o the benzol, naphthaline or pyridine series inacid solutions.

3. The method of making aryl-azo-alpha- :lpha-diaminopyridinehydrochlorides easily uble in water, which consists in mixing aqueoussolutions of the salts with hydrochlorides of other water solubleazo-dyes of the benzol, naphthaline or pyridine series, in hydrochloricacid solutions.

4. The step in the method of making arylazo-alpha-alpha-diaminopyridineeasily soluble in water, which consists in recrystallizing a mixture ofhydrochlorides of aryl-azoalpha-diaminopyridine, withpara-aminohenyl-azo benzo1-hydrochlorides, from boilmg water.

5. The step in the method of making arylazo-alpha-alpha-diaminopyridineeasily s01- uble in water, which consists in recrystallizing fromboiling water a mixture of aryl-azoalpha-diaminopyridine, and otherwater soluble salts of azodyes of the benzol, naphthaline or pyridineseries.

Signed at New York, in the county of New York and State of New York this20th day of September, A. D. 1927.

IWAN OSTROMISLENSKY.

